Can Strep Throat Cause Obsessive-Compulsive Disorder?

For years, researchers have wondered about a connection between children getting strep throat and later showing symptoms of obsessive-compulsive disorder (OCD).

Obsessive-compulsive disorder is a frequently debilitating condition affecting millions of Americans in which those afflicted think repetitive thoughts they don’t want to or perform compulsive, ritualistic behaviors they wish they didn’t have to—like washing their hands many, many times (sometimes until they bleed) or repeatedly checking a light switch to make sure it is off (even if they have to do so for an hour).

The thinking has been that strep throat bacteria trigger the production of antibodies that end up not only targeting strep, but “mistakenly” acting on an enzyme in the brain, which is involved in making brain chemical messengers. In so doing, the antibodies to the strep throat infection pathologically alter the balance of these chemical messengers.

Now, Israeli researchers have taken the theory one step further. A team at Tel Aviv University has created a lab model of how the process works. They take rats and expose them to strep bacteria and compare them to another group of rats who are not exposed to the bacteria. The ones exposed to the bacteria do indeed develop antibodies to the strep and high levels of those antibodies are, in fact, found bound to particular receptors in their brains. What’s more, these strep-exposed mice show compulsive behaviors like repeatedly and senselessly grooming themselves. Sounds a lot like repeatedly and senselessly washing one’s hands, right?

So, it is increasingly looking as though being infected by strep (as in, getting strep throat that isn’t very promptly treated) may be one significant reason people develop OCD. This is a stunning possibility, not only because of its implication for folks with that single condition, but because other conditions mimic OCD in many of their features—including autism.